1. Field of the Invention
The invention relates to a milling cutting insert having a square or triangular rake face which, as seen in plan view, is defined by a circumferential cutting edge having linear cutting edges and curved cutting corners.
2. Description of Related Art
During the “corner milling” of 90° shoulders, milling cutters are required which are fitted with cutting inserts which have a main lip and a facing lip (for smoothing the cut surface). The clamped cutting inserts project both beyond the end face of the rotatable tool holder and also laterally in order to be able to both produce the vertical wall parts and finish the cut bed wall. In most milling cutters, the cutting depth ap that can be achieved is limited by the length of the main lip. This becomes clear in particular in the usually lozenge-shaped cutting inserts, in which only in each case two opposite cutting corners with adjoining main and facing lips can be used on the rake face. A greater cutting depth is certainly provided by the cutting insert according to DE 601 12 993 T2, in which the acute-angled cutting corner is modified owing to the fact that the cutting edge sections directly adjoining the cutting corner are disposed substantially perpendicularly to one another, but here, too, the size of the main lips is restricted by the corresponding adjoining vertically arranged section. It is also known from said document that the cutting edge is designed to run in a downward-sloping manner toward an obtuse-angled corner.